I picked up a Northern radiator last year when I had the inline 6. It was cheap, not a direct fit for my 66 but it fit well, and is compatible with the LS swap I'm working on right now. Neat thing about their radiators is that they sell an electric fan setup for each one they make. My buddy has run Northern radiators in 3 of his last 4 projects with no issues.
It's P/N 209676 for anyone that is interested.